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SOIL PHYSICS AND MANAGEMENT 



Surface Tension and the Density of Certain Solutions 7 



application of some mineral fertilizer or in alkali soils. In either 

 of these cases some effect would undoubtedly be produced. 



3. Texture. - The smaller the soil particles the slower the 

 capillary movement, but theoretically the higher the water will 

 rise. This is true only in theory. The resistance to movement 

 becomes so great in very fine-grained soils that the water will not 

 rise as high as in medium-grained ones. Loughridge found that 

 in an adobe soil with 44.3 per cent of clay, a height of 46 inches 

 was reached in 195 days, while in a fine sandy soil the water attained 

 a height of 47 inches in 125 days. In a sand soil the water reached 

 its limit in six days. The movement of water in clay soils is very 

 slow, not only due to the extreme fineness of the ordinary clay 

 particles, but to the presence of colloids which doubtless hinder 

 the movement. 



In experiments with two soils water rose by capillarity 8.5 feet 

 in 90 days in loess (yellow fine sandy loam), while in white silt 

 loam soil with 0.8 per cent of organic matter it rose 9.5 feet in about 

 the same time. The loess contained practically no organic matter. 



4. Organic Matter. The presence of organic matter retards 

 capillary movement, due to the colloids present and the greater 

 porosity produced. The next table shows the movement of water 

 in soils by capillarity from a free water surface. The tubes were 

 one and one-half inches in diameter and five feet long. 



